mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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183 lines
6.2 KiB
C++
183 lines
6.2 KiB
C++
/* GStreamer
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* Copyright (C) <2010> Thiago Santos <thiago.sousa.santos@collabora.co.uk>
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* Copyright (C) <2018> Nicola Murino <nicola.murino@gmail.com>
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*
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* gstopencvutils.c: miscellaneous utility functions
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "gstopencvutils.h"
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#include <opencv2/core.hpp>
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/*
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The various opencv image containers or headers store the following information:
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- number of channels (usually 1, 3 or 4)
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- depth (8, 16, 32, 64...); all channels have the same depth.
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The channel layout (BGR vs RGB) is not stored...
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This gives us the following list of supported image formats:
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CV_8UC1, CV_8UC2, CV_8UC3, CV_8UC4
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CV_8SC1, CV_8SC2, CV_8SC3, CV_8SC4
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CV_16UC1, CV_16UC2, CV_16UC3, CV_16UC4
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CV_16SC1, CV_16SC2, CV_16SC3, CV_16SC4
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CV_32SC1, CV_32SC2, CV_32SC3, CV_32SC4
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CV_32FC1, CV_32FC2, CV_32FC3, CV_32FC4
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CV_64FC1, CV_64FC2, CV_64FC3, CV_64FC4
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Where the first part of the format name is the depth followed by a digit
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representing the number of channels.
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Note that opencv supports more that 4 channels.
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The opencv algorithms don't all support all the image types.
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For example findChessboardCorners() supports only 8 bits formats
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(gray scale and color).
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And, typically, this algorithm will convert the image to gray scale before
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proceeding. It will do so with something like this:
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cvtColor(srcImg, destImg, CV_BGR2GRAY);
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The conversion will work on any BGR format (BGR, BGRA, BGRx).
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The extra channel(s) will be ignored.
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It will also produce a result for any RGB format.
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The result will be "wrong" to the human eye and might affect some algorithms
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(not findChessboardCorners() afaik...).
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This is due to how RGB gets converted to gray where each color has a
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different weight.
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Another example is the 2D rendering API.
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It work with RGB but the colors will be wrong.
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Likewise other layouts like xBGR and ABGR formats will probably misbehave
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with most algorithms.
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The bad thing is that it is not possible to change the "default" BGR format.
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Safest is to not assume that RGB will work and always convert to BGR.
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That said, the current opencv gstreamer elements all accept BGR and RGB caps !
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Some have restrictions but if a format is supported then both BGR and RGB
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layouts will be supported.
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*/
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gboolean gst_opencv_parse_cv_mat_params_from_caps
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(GstCaps * caps, gint * width, gint * height, int *cv_type, GError ** err)
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{
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GstVideoInfo info;
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gchar *caps_str;
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if (!gst_video_info_from_caps (&info, caps)) {
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caps_str = gst_caps_to_string (caps);
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GST_ERROR ("Failed to get video info from caps %s", caps_str);
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g_set_error (err, GST_CORE_ERROR, GST_CORE_ERROR_NEGOTIATION,
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"Failed to get video info from caps %s", caps_str);
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g_free (caps_str);
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return FALSE;
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}
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return gst_opencv_cv_mat_params_from_video_info (&info, width, height,
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cv_type, err);
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}
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gboolean gst_opencv_cv_mat_params_from_video_info
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(GstVideoInfo * info, gint * width, gint * height, int *cv_type,
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GError ** err)
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{
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GstVideoFormat format;
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format = GST_VIDEO_INFO_FORMAT (info);
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if (!gst_opencv_cv_image_type_from_video_format (format, cv_type, err)) {
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return FALSE;
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}
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*width = GST_VIDEO_INFO_WIDTH (info);
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*height = GST_VIDEO_INFO_HEIGHT (info);
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return TRUE;
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}
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gboolean
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gst_opencv_cv_image_type_from_video_format (GstVideoFormat format,
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int *cv_type, GError ** err)
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{
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const gchar *format_str;
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switch (format) {
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case GST_VIDEO_FORMAT_GRAY8:
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*cv_type = CV_8UC1;
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break;
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case GST_VIDEO_FORMAT_RGB:
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case GST_VIDEO_FORMAT_BGR:
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*cv_type = CV_8UC3;
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break;
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case GST_VIDEO_FORMAT_RGBx:
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case GST_VIDEO_FORMAT_xRGB:
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case GST_VIDEO_FORMAT_BGRx:
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case GST_VIDEO_FORMAT_xBGR:
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case GST_VIDEO_FORMAT_RGBA:
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case GST_VIDEO_FORMAT_ARGB:
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case GST_VIDEO_FORMAT_BGRA:
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case GST_VIDEO_FORMAT_ABGR:
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*cv_type = CV_8UC4;
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break;
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case GST_VIDEO_FORMAT_GRAY16_LE:
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case GST_VIDEO_FORMAT_GRAY16_BE:
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*cv_type = CV_16UC1;
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break;
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default:
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format_str = gst_video_format_to_string (format);
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g_set_error (err, GST_CORE_ERROR, GST_CORE_ERROR_NEGOTIATION,
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"Unsupported video format %s", format_str);
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return FALSE;
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}
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return TRUE;
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}
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GstCaps *
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gst_opencv_caps_from_cv_image_type (int cv_type)
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{
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GstCaps *c = gst_caps_new_empty ();
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switch (cv_type) {
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case CV_8UC1:
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("GRAY8")));
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break;
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case CV_8UC3:
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("RGB")));
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("BGR")));
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break;
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case CV_8UC4:
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("RGBx")));
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("xRGB")));
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("BGRx")));
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("xBGR")));
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("RGBA")));
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("ARGB")));
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("BGRA")));
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gst_caps_append (c, gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("ABGR")));
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break;
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case CV_16UC1:
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gst_caps_append (c,
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gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("GRAY16_LE")));
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gst_caps_append (c,
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gst_caps_from_string (GST_VIDEO_CAPS_MAKE ("GRAY16_BE")));
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break;
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}
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return c;
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}
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